The long-range goal of the proposed research is to explain how trace minerals affect the development of dental caries. Experimental caries will be measured in rats receiving various dosages of selenium, cadmium and fluoride. We will measure the influence of simultaneous administration of selenium and cadmium on caries and the cariostatic properties of fluoride. We will also determine the minimum dosage of supplemental selenium causing cariostasis when added to a low selenium, caries promoting diet. Physical and chemical measurements on the molar teeth will be used to provide a biochemical mechanism for the observed effects of trace elements on dental caries.